Headrest for a vehicle

ABSTRACT

A headrest ( 10 ) for a vehicle seat has at least one base ( 11 ), such as a support rod or the like. A main body ( 12 ) is held on the base ( 11 ). A support part ( 13 ) having a head support surface ( 44 ) can move relative to the main body ( 12 ) forward in the forward direction (x) toward the back of the head of the vehicle occupant and back in the rearward direction (z). 
     The main body ( 12 ) is movable on the base ( 11 ) and can be shifted by at least one rotatable transmission element (K 1; 28, 30 ) in the forward direction (x) and in the rearward direction (z). At the same time, the support part, which moveable in the same direction with the main body ( 12 ) in the forward direction (x) and the rearward direction (z), is pivoted on the same rotatable transmission element (K 1; 28, 30 ).

The invention relates to a headrest for a vehicle seat, such as is knownfrom to the introductory clause of claim 1 of EP 0,974,484.

The known headrest of EP 0,974,484 is a crash-active headrest wherein,when a crash signal is generated, the support part that has a headsupport surface and that is supported on a rear main body is shiftedforward in a forward or X direction toward the back of the head of thevehicle occupant. Since in an accident the travel time is relativelyshort and hence the horizontal forward travel has to be effectedrelatively quickly, the horizontal travel is often relatively short inthe case of crash-active headrests of this type for physiologicalreasons.

However, in actual use as shown by way of example in EP 730,993 (see[0024] here], it is necessary to have greater horizontal travel.

Headrests with longer horizontal travel are known, for example, from DE31 09 592. In the case of this known headrest (see DE 31 09 592, FIG.2), the entire head including its padding is shifted horizontallyforward by a rack-and-pinion linkage relative to a support formed by twosupport rods. Since the rack must fit with its entire horizontal lengthin the casing of the headrest, the known headrest of DE 31 09 592 mustbe very deep, i.e. have a relatively voluminous design.

Based on EP 0,974,484 mentioned above, the object of the invention is tofurther develop the known headrest such that, despite a relativelycompact design, it permits relatively large adjustment pathshorizontally.

This object is attained with the features of the introductory clause ofclaim 1 together with the characterizing clause thereof in that the mainbody is guided in a movable manner on the support and is movable by atleast one rotatable transmission element in the forward and rearwarddirections and that the support part is pivoted in the forward andrearward direction on the same rotatable transmission element, moveablein the same direction as the main body.

In contrast to the known headrest of EP 0,974,484, in which the mainbody is arranged fixedly on the support with respect to the horizontaldirection, with the known one, on a support tube stirrup, the inventionhas a main body movable relative to the base. Due to the fact that theheadrest according to the invention furthermore has a support parthaving a head support surface and is moveable relative to the main body,a superimposition or addition of the two horizontal travels results,namely of the travel of the main body and of the travel of the supportpart.

Due to the fact that, according to the invention, the main body ishorizontally moveable in the forward and rearward direction by at leastone rotatable transmission element relative to the support, and in thatthe support part as well as the main body are both pivoted on the samerotatable transmission element to move in the same direction onrotation, in addition, the desire for a compact design is supported byreducing the number of parts with the headrest according to theinvention.

With the features of claim 1, the invention has two differentembodiments. A first embodiment corresponds to the features of claims 2through 9, while a second embodiment is characterized by the featuresaccording to claims 10 through 16.

Accordingly, according to the first embodiment the one or more rotatabletransmission elements are each a lever, and each rotatable transmissionelement is part of a coupling mechanism.

That coupling mechanism has at least four parts and thereby forms aparallelogrammatic linkage with two levers and two coupling links. Abasic embodiment of a parallelogrammatic linkage of this type is shown,for example, in the textbook by Werner Krause, Konstruktionselemente derFeinmechanik (1993; Carl Hanser Verlag, Munich Vienna) page 724, table13.11.1 (parallelogrammatic linkage).

In a further embodiment of the invention, the base, which can be, forexample, two support rods or two support tubes optionally combined witha crosspiece, has an extension extending parallel to the rearward andforward direction and forming pivots for ends of the respective leverand horizontally or approximately horizontally spaced from one another.

In detail, according to a particular embodiment of the invention, aparallelogrammatic linkage is formed with parts of the headrest suchthat the main body has a first extension projecting in the forwarddirection and forming a first coupling link is supported in the centerpart of a lever by a respective pivot, while the support part has asecond extension projecting rearward, forming a second coupling link,and supported by a pivot each on an end of a respective lever extendingaway from the extension of the base.

The above referenced embodiment according to the invention can be suchthat the two levers are generally vertical and pivoted on the extensionof the base.

On the other hand, according to a preferred embodiment the inventionalternatively provides that the two levers extend downward from and arepivotally hung from the extension of the base.

Although it is basically possible with the invention to arrange all ofthe geometric pivot joint axes of the pivots vertically and parallel,according to a preferred embodiment according to the invention the pivotaxes of the pivots of the one or more rotatable transmission elements,the levers and the is coupling links extend horizontally and parallel toone another.

The second embodiment according to the invention has two rotatabletransmission elements that are supported on the base with parallel axesby two pivots spaced from one another.

A special feature of the second embodiment according to the inventionlies in that each rotatable transmission element is a gear with an armprojecting radially from the gear axis and having an arm pivot on whicha rear end of a control link is supported by a rear pivot, the front endof which control link is supported on the support part by a front pivotand extends toward the rear from the latter, while a gear rack extensionprojecting from the main body in the forward direction forms arack-and-pinion linkage jointly with the gear.

A further development according to the invention in which a cantedposition of the front support part is automatically excluded, lies inthat each control link is a double-arm lever connected in a movablemanner to a synchronizing mechanism by a rear additional pivot spacedfrom the respective arm pivot.

In detail, in this further embodiment of the invention the synchronizingmechanism has two linking gears pivoted on the rear side of the supportpart with parallel axes, in engagement with one another, having the samedimensions, and symmetrical to one another, which linking gears eachform an eccentric pivot bearing point for a one front end of arespective coupling link extending toward the support part and having arear end remote from the support part and pivoted on and additionalpivot of the respective control link.

In the context described above, in additional a space-savingconstruction is achieved in that the two coupling links cross each other

Furthermore, to reduce the number of parts through the specialfunctional incorporation of the base, the invention provides that thebase has two support rods or tubes extending parallel to one another andthat the support rods or tubes form bearings for the gears of therack-and-pinion linkage.

It is basically possible for the axes of all of the pivots to extendhorizontally and parallel to one another. However, the preferred secondembodiment according to the invention is characterized in that the axesof all of the pivots and the gear bearings extend vertically andparallel to one another.

Preferred illustrated embodiments according to the invention are shownin the drawings, therein:

FIG. 1 is a vertical section through a first embodiment of a headrest ina rest position thereof,

FIG. 2 shows the headrest of FIG. 1 in an operating position extendedhorizontally,

FIG. 3 is a horizontal section through a second embodiment of a headrestin the rest position thereof, and

FIG. 4 shows the headrest of FIG. 3 in the extended operational positionthereof.

In the following description of the drawings, the same reference numbersare used for the same parts or for parts operating in an analogousmanner in a different embodiment.

The headrest 10 of the first embodiment shown in FIGS. 1 and 2 has aU-shaped base 11, a main body 12, and a support part 13. The base 11 hastwo support rods 14 of which only one is visible in FIGS. 1 and 2. Thelower ends of the support rods 14 are fitted in a manner not shown inmounting sleeves on the seat-back so as to be if necessary verticallyadjustable.

At its upper end, the base 11 is provided with an extension 15. Theextension 15 extends parallel or at least essentially parallel forwardin the direction x and back in the rearward direction z.

The extension 15 has two pivots 16 and 17 spaced from each other by aspacing in a horizontal direction h for upper ends 18 and 19 ofrespective levers K1 and K2. The horizontal spacing h (see double arrow)is in the forward and rearward directions x and z.

The main body 12 has a first extension that projects forward in aforward direction x and that forms a first coupling link C1 joined tocenters of each lever K1 and K2 at respective pivots 20 and 21. Thesupport part 13 itself has a second extension that projects in therearward direction z and that forms a second coupling link C2 carryingpivots 22 and 23 on ends 24 and 25 of the levers K1 and K2 remote fromthe extension 15 of the base 11.

The two levers K1 and K2 extend downward from and are pivotally hungfrom the extension 15 of the base 11.

FIGS. 1 and 2 also show that the pivots 16, 17, 20, 21, 22 and 23 of thelevers K1 and K2 and the axes of the coupling links C1 and C2 are markedwith crosses and all extend horizontally and parallel to one another.

The structure shown by FIGS. 1 and 2 of the levers K1 and K2 and thecoupling links C1 and C2 forms a parallelogrammatic linkage whose modeof operation is easily seen by a comparison of FIGS. 1 and 2.

In order to extend the support part 13 in the forward direction x fromthe rest position of FIG. 1 into the operating position of FIG. 2, thepassenger grasps the support part 13 and pulls it forward in thedirection x, for example, of FIG. 2 into the frontmost end position.Because of the linkage, the main body is also entrained by this action.Locking is advantageous in that horizontally advanced position. Lockingmeans in this regard are shown diagrammatically in FIG. 2 by a hiddenhole arrangement 26 and a hidden lock pin 27 that can be operated fromoutside the headrest 10.

FIGS. 1 and 2 also show that the headrest 10 can have twoparallelogrammatic linkages K1, K2; C1, C2 next to each other.

As shown in FIGS. 1 and 2 it is also conceivable that, during movementfrom the rest position of FIG. 1 into the extended adjustment positionof FIG. 2, the main body 12 and the support part 13 each move through atravel of magnitude 1, so that total travel in the direction x with themagnitude 2 results for the support part 13.

The second embodiment of the headrest has two rotatable transmissionelements each formed by a gear 28 having a respective axis 29 from whicha respective arm 30 extends radially. Each arm 30 has an arm pivot 31 onwhich a rear end 33 of a respective control link L is supported by arear pivot 32. A front end 34 of each control link is supported on thesupport part 13 at a is respective front pivot 35. The control link Lextends rearward from the support part 13, and racks 36 projecting fromthe main body 12 in the forward direction x form together with the gears28 respective rack-and-pinion assemblies.

Each control link L is a double-arm lever linked to a synchronizingmechanism shown generally at G at a rear additional pivot 37 spaced fromthe respective arm pivot 31.

The synchronizing mechanism G has two symmetrically oriented and meshingsector gears 38 rotatable on the rear of the support part 13 aboutparallel axes and of the same dimensions, these linking gears beingsupported by bearings 43 inside the support part 13. The gears 28 and 38are advantageously formed as spur gears and straight-cut.

The linking gears 38 each form an eccentric pivot 39 for a front end 40of a coupling link 41 extending toward the part 13 and having a rear end46 remote from the support part 13 and each rotatable on a respectivepivot 37 on a respective one of the control links L. The two couplinglinks 41 cross.

Otherwise, the base 11 has two support rods or tubes 14 extendingparallel to one another, the support rods or tubes 14 each forming abearing 42 for the respective gear 28 of the respective rack-and-pinionlinkage 28, 36.

Furthermore, FIGS. 3 and 4 show that the pivots 31, 32, 35, 37, and 39and the bearing axes of the gears 28 and 38 extend vertically andparallel to one another.

The function of the second embodiment of the headrest 10 can be easilyunderstood by a comparison of FIGS. 3 and 4. When a passenger grasps thefront support part 13, pulling it in the forward direction x,—as withthe headrest of FIGS. 1 and 2—the main body 12 as well as the supportpart 13 are pulled forward by the drive connection, the support part 13entraining the main body 12.

At the same time, the synchronizing mechanism G ensures that the supportpart 13 with its head support surface 44 stays parallel to the main body12 when moving horizontally. The horizontal travels are also additivewith the headrest of FIGS. 3 and 4. When accordingly the main body 12and the support part 13 cover a horizontal travel with the amount 1 fromthe rest position of FIG. 1 to the extended operating position of FIG.2, a travel with the amount 2 results for the support part 13 as awhole.

Like the first embodiment (FIGS. 1 and 2), a hidden hole arrangement 26with a hidden pin 27 (all indicated diagrammatically by broken lines) isalso provided with the second embodiment (see FIG. 4). The hidden pinengages in the teeth of one of the gears 28 and in this manner blocksthe headrest 10 in its extended operating position.

1. A headrest for a vehicle seat, having a main body held on at leastone base, such as a support rod or the like, and a support part having ahead support surface, guided so as to be movable relative to the mainbody, and movable forward in a forward direction toward the back of thehead of a vehicle occupant and back in a rearward direction wherein themain body is movable relative to the base can be moved by at least onerotatable transmission element in the forward direction and in therearward direction, and that the support part, which is moveable in thesame direction as the main body in the forward direction and therearward direction, is pivoted on the same rotatable transmissionelement.
 2. The headrest according to claim 1 wherein the rotatabletransmission element is a lever and that the rotatable transmissionelement is a part of a respective coupling mechanism.
 3. The headrestaccording to claim 2 wherein the coupling mechanism has four parts. 4.The headrest according to claim 3 wherein the four-part couplingmechanism is a parallelogrammatic linkage with two levers and twocoupling links.
 5. The headrest according to claim 4 wherein the basehas an extension extending in the forward direction and rearwarddirection and carrying two pivots each for a respective end of a leverand spaced in or approximately in the horizontal direction spaced fromone another.
 6. The headrest according to claim 2 wherein the main bodyhas a first extension projecting in the forward direction and forming afirst coupling link and is supported in center part of respective leversby respective pivots, while the support part has a second extensionprotecting rearward and forming a second coupling link carrying pivotseach on an end of a respective lever extending away from the extensionof the base.
 7. The headrest according to claim 6 wherein the two aregenerally vertical and are pivoted on the extension of the base.
 8. Theheadrest according to claim 6 wherein the two levers extend downwardfrom and are pivotally suspended on the extension of the base.
 9. Theheadrest according to claim 8 wherein axes defined by the pivots of theat least one rotatable transmission element, the levers and the couplinglinks extend horizontally and parallel to one another.
 10. The headrestaccording to claim 1, wherein there are two such rotatable transmissionelements supported on respective pivots spaced from one another on thebase and having parallel axes.
 11. The headrest according to claim 10wherein each rotatable transmission element is a gear centered on anaxis and having a radially projecting arm forming an arm pivot andhaving a rear pivot to which is coupled a rear end of a respectivecontrol link having a front end supported on and extending rearward froma front pivot on the support part, a gear rack extension projecting fromthe main body in the forward direction forming with the gear arack-and-pinion linkage.
 12. The headrest according to claim 10 whereineach control link is a double-arm lever connected in a movable manner toa synchronizing mechanism by another rear pivot spaced from therespective arm pivot.
 13. The headrest according to claim 12 wherein thesynchronizing mechanism has two linking gears pivoted on parallel axeson a rear side of the support part, meshing with each other, having thesame dimensions, and symmetrically oriented relative to each other, thelinking gears each forming an eccentric pivot for a front end of arespective coupling link extending toward the support part and having arear end remote from the support part and pivoted on the additionalpivot of the respective control link.
 14. The headrest according toclaim 13 wherein the two coupling links cross each other.
 15. Theheadrest according to claim 10 wherein the base has two support rods ortubes extending parallel to one another and that the support rods ortubes each form a bearing for a respective one of the gears of therespective rack-and-pinion linkage.
 16. The headrest according to claim10 wherein the axes of all the pivots and the gear bearings extendvertically and parallel to one another.
 17. A headrest for a vehicleseat, the headrest comprising: a base fixed to the seat; a main bodyshiftable horizontally forward and rearward relative to the base; asupport part shiftable horizontally forward and rearward relative tobase and to the main body and engageable with a back of a head of anoccupant of the seat; an element rotatable on the base; means couplingthe element to the support part for horizontally forward and rearwardshifting the support part on rotation of the element on the base inforward and rearward directions; and means coupling the element to themain body for horizontally shifting the main body codirectionally withthe support part on rotation of the element on the base in the forwardand rearward directions.
 18. The headrest defined in claim 17 whereinthe element is a pair of levers having first ends pivoted on the base athorizontally spaced parallel axes and second ends spaced from the firstends, the means coupling the element to the support being pivots betweenthe second ends and the support part, the means coupling the element tothe main body being pivots between the main body and locations on thelevers between the respective ends.
 19. The headrest defined in claim 18wherein the base has a horizontal extension on which the first ends arepivoted, the support part has a horizontal extension on which the secondends are pivoted, and the main body has a horizontal extensionvertically between the extensions of the base and support part and onwhich the locations of the levers are pivoted.
 20. The headrest definedin claim 17 wherein the means coupling the element to the main body is arack on the main body and a gear meshing with the rack and fixed to therotatable element.